The invention concerns a device for withdrawing body fluid with a lancing element that can puncture the skin of a body part and which has a receiving structure for receiving body fluid obtained from the puncture and a lancing drive for a forward and retracting movement of the lancing element, wherein the duration of the retracting movement is longer (preferably many times longer) than the duration of the forward movement. The invention additionally concerns a corresponding method for withdrawing body fluid.
For blood sugar tests it has already been proposed that automatic withdrawal of sample from the skin by puncture with a lancing element can be accomplished by carrying out the retraction movement considerably more slowly than the forward movement so that an adequate amount of sample for the test can be reliably collected. In so doing, the position of the transition from rapid to slower movement should be at only such a depth in the tissue that a receiving structure incorporated into the lancing element still makes a reliable contact with the escaping liquid. A lancing system is described in WO 2007/073870 which allows the transition position to be kept constant despite a variable lancing depth but requires considerable technical complexity.